1. Field of the Invention
The invention relates to an improved hinge element for pivotally mounting a door to a cover dead front of an enclosure which generally covers and protects circuit breaker handles in a load center for a residential dwelling or commercial building.
2. Description of the Prior Art
Circuit breaker load centers in commercial and residential constructions are well-known. The load center generally is covered and protected by an enclosure comprising an inner cover with several twist-out sections for receiving the handles of the circuit breakers, a cover dead front which generally fits into and over the wall opening where the handles are located, and a door pivotally mounted to the cover dead front which provides access to the handles of the circuit breakers extending through the removed twist-out sections of the inner cover. The inner cover may be integrally formed with the cover dead front or it may be a separate piece connected by screws to the cover dead front and adjustable relative thereto. The front surface of the cover dead front forms a recess portion which receives the door and which terminates to form a peripheral ledge which, in turn, forms a central opening in the cover dead front for access to the handles of the circuit breakers extending in the twist-out sections which have been removed for this purpose. An aperture is provided along an edge of the recess portion of the cover dead front for receiving a hinge element which pivotally mounts the door to the cover dead front. If the inner cover and the cover dead front are integrally formed, usually a wide gap exists between the aperture in the cover dead front which receives the hinge element and the peripheral ledge of the central opening in the cover dead front on the back surface of the cover dead front. If the inner cover and the cover dead front are separate pieces and the inner cover is adjustable relative to the cover dead front, the end walls of the cover dead front may be caused to move into this gap between the aperture in the cover dead front for receiving the hinge element and the peripheral ledge of the central opening in the cover dead front resulting in a limited amount of space in this gap.
Generally, the door of the closure has an aperture which is located along a longitudinal edge of the door and which corresponds in number to the apertures in the cover dead front.
The hinge element is U-shaped with spaced-apart wall members bridged by a curved portion and retaining means on each wall member for fixing the hinge element in position. In the mounting of the door onto the cover dead front, the hinge element is installed with one of the wall members being received in the door aperture and in the aperture in the cover dead front, and the other wall member being received in the aperture in the cover dead front with the longitudinal edge of the door adjacent to the door aperture being received in the curved portion of the hinge element.
One form of the retaining means on the hinge element, which is presently used by the former owner of the assignee of this invention, involves a bendable tab on each spaced-apart wall member which is manually bent in an outward direction once the hinge element is installed. These tabs are located diagonally relative to each other and are formed by forming a slanted slot into a lateral edge of each wall member. This hinge element is generally made of a hard material such as stainless steel, which requires the robs to be manually bent by a tool such as pliers. This hinge element is generally used when the enclosure for the circuit breaker handles comprises an integrally formed inner cover and cover dead front in that there is enough space existing in the gap between the aperture in the cover dead front and the peripheral ledge forming the central opening in the cover dead front so that the tab closest to the central opening in the cover dead front can be manually bent toward this central opening without encountering interference from the peripheral ledge of the central opening.
Another form of the retaining means tier a U-shaped hinge element for an enclosure in a load center involves a central projection which is punched out of each wall member and which points toward the curved portion of the hinge element. This type of hinge element is generally made of brass which provides a degree of resiliency such that when the hinge element is installed, the central projections are pushed inwardly by the aperture walls and spring outwardly once the wall members of the hinge element pass through the aperture. This provides an automatic and positive engagement of the hinge element without any manual intervention by a workman. This kind of hinge element is generally used when the enclosure comprises an inner cover which is separate from and adjustable relative to the cover dead front where the end walls of the inner cover take up most of the space in the gap between the aperture in the cover dead front and the peripheral ledge of the central opening of the cover dead front as the extension of the central projections on the wall members of the hinge element is minimal requiring a minimal amount of space for retaining the hinge element in the cover dead front.
This latter type of hinge element may be advantageous in that it can easily be installed as it automatically snaps into place without manual intervention. However, it has some drawbacks in that the central projections can easily shear off due to their construction and the type of material used in this hinge element. Additionally, the central projections provide a minimal latching surface for the hinge device thereby creating a precarious situation where the hinge element can be dislodged from its holding position.
There remains, therefore, a very real and substantial need for a stronger U-shaped hinge element which provides an increased holding force and a more sturdy construction for the retaining means on each wall member so that the retaining means cannot be easily sheared off.